A common and well known form of harvesting machine is a rotary combine. Rotary combines are available in various designs and models to perform the basic functions of harvesting, threshing, and cleaning of grain or other crop materials.
A typical combine includes a crop harvesting apparatus which reaps planted grain stalks and then feeds the grain stalks to a separating or threshing apparatus. The grain stalks or other crop harvested in the field is rearwardly moved from the crop harvesting apparatus toward the threshing apparatus by a crop feeder mechanism.
The threshing apparatus includes a power driven rotor mounted inside a stationary cylindrical threshing cage. The rotor is supported at opposite ends by bearings. Moreover, the rotor has a series of blades at its forward end defining an impeller. The rotor threshes and separates the grain from the material other than grain. In such a combine, which has been available for a number of years, the grain is threshed several times repeatedly, but gently, as its spirals around the rotor and passes through openings in the threshing cage. Essentially, most material other than grain stays within the threshing cage and is directed out the rear of the combine.
Extending forwardly from the threshing cage and surrounding the impeller is a transition housing. Transition housing has an inlet end which opens to the front of the combine and an outlet end which opens to the threshing apparatus. The feeder mechanism exhausts crop to the inlet end of the transition housing. The internal surface of the transition housing is provided with a series of helically shaped transport vanes for axially conveying or displacing crop material rearwardly between the feeder mechanism and the threshing cage.
The rotor of the threshing apparatus is rotatably driven at speeds ranging between 400 and 1100 rpm. Rotor speed will be determined as a function of the crop being harvested. The impeller blades on the front end of the rotor, turn at the same speed as the rotor. The impeller blades accept crop from the feeder mechanism and are intended to move the crop peripherally outward toward the helical transport vanes for subsequent delivery to the rotor of the threshing apparatus.
Residual crop that is not accepted by the blades or is not peripherally moved toward the helical transport vanes tends to whirl about a forward face of the impeller. Such residual crop also has a tendency to wrap about the front bearing of the rotor causing operational problems for the combine. As will be appreciated, removal and cleaning of such entangled crop from about the front rotor bearing is a time consuming process which detracts from the combine's efficiency. Moreover, residual crop creates a back-feed problem for the feeder mechanism. As will be understood, such residual crop consumes power and destroys the effectiveness of the combine.
Therefore, what is desired is a device which improves crop delivery from the feeder mechanism to the transport vanes for subsequent delivery to the threshing apparatus in a manner reducing or avoiding back-feed to the feeder mechanism and prevents crop from wrapping about the front rotor bearing.